The present invention is a method to determine a detailed model of composition of a crude oil, a crude oil distillate, or a petroleum process stream. The successful development of the technology described herein will reduce the need for detailed analytical analysis, e.g. high-detail hydrocarbon analysis (HDHA) of refinery feeds, intermediate streams and products, and will enhance the utility of Real Time Optimization (RTO) and Optimizable Refinery Models (ORMs) by allowing more frequent (easier, cheaper, faster) analysis of actual feedstocks and products.
Perry and Brown (U.S. Pat. No. 5,817,517) demonstrated the use of FT-IR to estimate constituent classes of molecules (e.g. “lumps”) in streams such as feeds to catalytic cracking units. This method does not provide the detailed compositional information of the current invention.
High-Detailed Hydrocarbon Analysis (HDHA) is an analytical protocol for measuring a detailed hydrocarbon composition of a crude oil or crude distillate or petroleum process stream. The acronym HDHA is also used for the Model of Composition produced by this analysis. The specific analytical protocol and the molecular information contained in the HDHA depend on the boiling range of the material being analyzed.                For a naphtha stream boiling below approximately 350° F., a detailed analysis can be accomplished via gas chromatography using methods such as ASTM D 5134, D 5443, and D 6729, D 6730 or other similar methods. These analyses provide complete molecular descriptions, distinguishing among isomers.        For a kerosene stream with a nominal boiling range of 350° F.-550° F., a detailed analysis can be accomplished using the method of Qian, et. al. (US 2007/0114377 A1) This analysis distinguishes among the molecular types in the kerosene, but does not discern exact molecular (isomeric) structure.        An analytical protocol for analyzing gas oil materials boiling between approximately 550° F. and 1050° F. is described below in Appendices A-C. This heavy HDHA (H-HDHA) is a complex protocol involving various chromatographic separations followed by elemental and mass spectral analyses of separated fractions. Again, this analysis distinguishes among molecular types but not among isomers.        For vacuum resid materials boiling above 1050° F., individual molecules cannot be measured for the entire boiling range. Jaffe, Freund and Olmstead (Extension of Structure-Oriented Lumping to Vacuum Residua, Jaffe, Stephen B.; Freund, Howard; Olmstead, William N.; Ind. Eng. Chem. Res. V 44, p. 9840-9852, 2005.) described how molecular compositions can be inferred by extrapolating the gas oil compositions so as to be consistent with other measurements such as elemental analysis (C, H, S, N, O, Ni and V), average molecular weight, Nuclear Magnetic Resonance (NMR), infrared (IR), ultra-violet visible (UV-visible) spectroscopy and separation techniques such as short path distillation, high performance liquid chromatography (HPLC), gas chromatography (GC) and solvent solubility.        For wider boiling materials such as crude oils, the HDHA analysis requires that the total material be distilled into naphtha, kerosene, gas oil and resid fractions which are separately analyzed via the protocols discussed above. The distillation can be accomplished via methods such as ASTM D 2892 and D 1160. The data for the individual cuts is then combined into a complete description of the wider boiling material.        
HDHA compositions are currently measured on different process streams. These detailed compositions are used in the development of SOL-based refinery process models (see R. J. Quann and S. B. Jaffe (Ind. Eng. Chem. Res. 1992, 31, 2483-2497 and Quann, R. J.; Jaffe, S.B. Chemical Engineering Science v51 n 10 pt A May 1996. p 1615-1635, 1996), and serve as a reference “template” of typical stream compositions. The HDHA method, while giving detailed results, is also elaborate and expensive, and is not suited for on-line implementation. Therefore, when composition of a sample is required for use in process control or optimization, synthesis techniques (step 2 of the current invention) are typically used to adjust a fixed reference template selected based on prior experience to match measured property targets such as API and boiling curve. However, systematic reference selection techniques do not exist and the quality of the eventually estimated composition crucially depends upon the reference. Estimating composition from properties can be difficult to impossible if poor judgment and criteria are used to select the reference. Availability of a whole sample, multivariate analytical techniques such as FTIR, supply a crucial piece of the composition puzzle that can be used to construct this critical “reference” composition. Brown (U.S. Pat. No. 6,662,116 B2) has described the use of FTIR measurements and a “Virtual Assay” analysis methodology for estimating for crude assay information. This analysis methodology can be used to estimate HDHA data, but the resultant composition estimates may not adequately match measured property values. The estimated compositions, however, are often superior references for the synthesis of an accurate detailed composition.